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1/*
2*******************************************************************************
3*
93a37866 4* Copyright (C) 1999-2010, International Business Machines
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5* Corporation and others. All Rights Reserved.
6*
7*******************************************************************************
8* file name: utf16.h
9* encoding: US-ASCII
10* tab size: 8 (not used)
11* indentation:4
12*
13* created on: 1999sep09
14* created by: Markus W. Scherer
15*/
16
17/**
18 * \file
19 * \brief C API: 16-bit Unicode handling macros
20 *
21 * This file defines macros to deal with 16-bit Unicode (UTF-16) code units and strings.
22 * utf16.h is included by utf.h after unicode/umachine.h
23 * and some common definitions.
24 *
25 * For more information see utf.h and the ICU User Guide Strings chapter
93a37866 26 * (http://icu-project.org/userguide/strings.html).
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27 *
28 * <em>Usage:</em>
29 * ICU coding guidelines for if() statements should be followed when using these macros.
30 * Compound statements (curly braces {}) must be used for if-else-while...
31 * bodies and all macro statements should be terminated with semicolon.
32 */
33
34#ifndef __UTF16_H__
35#define __UTF16_H__
36
37/* utf.h must be included first. */
38#ifndef __UTF_H__
39# include "unicode/utf.h"
40#endif
41
42/* single-code point definitions -------------------------------------------- */
43
44/**
45 * Does this code unit alone encode a code point (BMP, not a surrogate)?
46 * @param c 16-bit code unit
47 * @return TRUE or FALSE
48 * @stable ICU 2.4
49 */
50#define U16_IS_SINGLE(c) !U_IS_SURROGATE(c)
51
52/**
53 * Is this code unit a lead surrogate (U+d800..U+dbff)?
54 * @param c 16-bit code unit
55 * @return TRUE or FALSE
56 * @stable ICU 2.4
57 */
58#define U16_IS_LEAD(c) (((c)&0xfffffc00)==0xd800)
59
60/**
61 * Is this code unit a trail surrogate (U+dc00..U+dfff)?
62 * @param c 16-bit code unit
63 * @return TRUE or FALSE
64 * @stable ICU 2.4
65 */
66#define U16_IS_TRAIL(c) (((c)&0xfffffc00)==0xdc00)
67
68/**
69 * Is this code unit a surrogate (U+d800..U+dfff)?
70 * @param c 16-bit code unit
71 * @return TRUE or FALSE
72 * @stable ICU 2.4
73 */
74#define U16_IS_SURROGATE(c) U_IS_SURROGATE(c)
75
76/**
77 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
78 * is it a lead surrogate?
79 * @param c 16-bit code unit
80 * @return TRUE or FALSE
81 * @stable ICU 2.4
82 */
83#define U16_IS_SURROGATE_LEAD(c) (((c)&0x400)==0)
84
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85/**
86 * Assuming c is a surrogate code point (U16_IS_SURROGATE(c)),
87 * is it a trail surrogate?
88 * @param c 16-bit code unit
89 * @return TRUE or FALSE
90 * @stable ICU 4.2
91 */
92#define U16_IS_SURROGATE_TRAIL(c) (((c)&0x400)!=0)
93
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94/**
95 * Helper constant for U16_GET_SUPPLEMENTARY.
96 * @internal
97 */
98#define U16_SURROGATE_OFFSET ((0xd800<<10UL)+0xdc00-0x10000)
99
100/**
101 * Get a supplementary code point value (U+10000..U+10ffff)
102 * from its lead and trail surrogates.
103 * The result is undefined if the input values are not
104 * lead and trail surrogates.
105 *
106 * @param lead lead surrogate (U+d800..U+dbff)
107 * @param trail trail surrogate (U+dc00..U+dfff)
108 * @return supplementary code point (U+10000..U+10ffff)
109 * @stable ICU 2.4
110 */
111#define U16_GET_SUPPLEMENTARY(lead, trail) \
112 (((UChar32)(lead)<<10UL)+(UChar32)(trail)-U16_SURROGATE_OFFSET)
113
114
115/**
116 * Get the lead surrogate (0xd800..0xdbff) for a
117 * supplementary code point (0x10000..0x10ffff).
118 * @param supplementary 32-bit code point (U+10000..U+10ffff)
119 * @return lead surrogate (U+d800..U+dbff) for supplementary
120 * @stable ICU 2.4
121 */
122#define U16_LEAD(supplementary) (UChar)(((supplementary)>>10)+0xd7c0)
123
124/**
125 * Get the trail surrogate (0xdc00..0xdfff) for a
126 * supplementary code point (0x10000..0x10ffff).
127 * @param supplementary 32-bit code point (U+10000..U+10ffff)
128 * @return trail surrogate (U+dc00..U+dfff) for supplementary
129 * @stable ICU 2.4
130 */
131#define U16_TRAIL(supplementary) (UChar)(((supplementary)&0x3ff)|0xdc00)
132
133/**
134 * How many 16-bit code units are used to encode this Unicode code point? (1 or 2)
135 * The result is not defined if c is not a Unicode code point (U+0000..U+10ffff).
136 * @param c 32-bit code point
137 * @return 1 or 2
138 * @stable ICU 2.4
139 */
140#define U16_LENGTH(c) ((uint32_t)(c)<=0xffff ? 1 : 2)
141
142/**
143 * The maximum number of 16-bit code units per Unicode code point (U+0000..U+10ffff).
144 * @return 2
145 * @stable ICU 2.4
146 */
147#define U16_MAX_LENGTH 2
148
149/**
150 * Get a code point from a string at a random-access offset,
151 * without changing the offset.
152 * "Unsafe" macro, assumes well-formed UTF-16.
153 *
154 * The offset may point to either the lead or trail surrogate unit
155 * for a supplementary code point, in which case the macro will read
156 * the adjacent matching surrogate as well.
157 * The result is undefined if the offset points to a single, unpaired surrogate.
158 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
159 *
160 * @param s const UChar * string
161 * @param i string offset
162 * @param c output UChar32 variable
163 * @see U16_GET
164 * @stable ICU 2.4
165 */
166#define U16_GET_UNSAFE(s, i, c) { \
167 (c)=(s)[i]; \
168 if(U16_IS_SURROGATE(c)) { \
169 if(U16_IS_SURROGATE_LEAD(c)) { \
170 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)+1]); \
171 } else { \
172 (c)=U16_GET_SUPPLEMENTARY((s)[(i)-1], (c)); \
173 } \
174 } \
175}
176
177/**
178 * Get a code point from a string at a random-access offset,
179 * without changing the offset.
180 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
181 *
182 * The offset may point to either the lead or trail surrogate unit
183 * for a supplementary code point, in which case the macro will read
184 * the adjacent matching surrogate as well.
185 * If the offset points to a single, unpaired surrogate, then that itself
186 * will be returned as the code point.
187 * Iteration through a string is more efficient with U16_NEXT_UNSAFE or U16_NEXT.
188 *
189 * @param s const UChar * string
190 * @param start starting string offset (usually 0)
93a37866 191 * @param i string offset, must be start<=i<length
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192 * @param length string length
193 * @param c output UChar32 variable
194 * @see U16_GET_UNSAFE
195 * @stable ICU 2.4
196 */
197#define U16_GET(s, start, i, length, c) { \
198 (c)=(s)[i]; \
199 if(U16_IS_SURROGATE(c)) { \
200 uint16_t __c2; \
201 if(U16_IS_SURROGATE_LEAD(c)) { \
202 if((i)+1<(length) && U16_IS_TRAIL(__c2=(s)[(i)+1])) { \
203 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \
204 } \
205 } else { \
93a37866 206 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
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207 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
208 } \
209 } \
210 } \
211}
212
213/* definitions with forward iteration --------------------------------------- */
214
215/**
216 * Get a code point from a string at a code point boundary offset,
217 * and advance the offset to the next code point boundary.
218 * (Post-incrementing forward iteration.)
219 * "Unsafe" macro, assumes well-formed UTF-16.
220 *
221 * The offset may point to the lead surrogate unit
222 * for a supplementary code point, in which case the macro will read
223 * the following trail surrogate as well.
224 * If the offset points to a trail surrogate, then that itself
225 * will be returned as the code point.
226 * The result is undefined if the offset points to a single, unpaired lead surrogate.
227 *
228 * @param s const UChar * string
229 * @param i string offset
230 * @param c output UChar32 variable
231 * @see U16_NEXT
232 * @stable ICU 2.4
233 */
234#define U16_NEXT_UNSAFE(s, i, c) { \
235 (c)=(s)[(i)++]; \
236 if(U16_IS_LEAD(c)) { \
237 (c)=U16_GET_SUPPLEMENTARY((c), (s)[(i)++]); \
238 } \
239}
240
241/**
242 * Get a code point from a string at a code point boundary offset,
243 * and advance the offset to the next code point boundary.
244 * (Post-incrementing forward iteration.)
245 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
246 *
247 * The offset may point to the lead surrogate unit
248 * for a supplementary code point, in which case the macro will read
249 * the following trail surrogate as well.
250 * If the offset points to a trail surrogate or
251 * to a single, unpaired lead surrogate, then that itself
252 * will be returned as the code point.
253 *
254 * @param s const UChar * string
93a37866 255 * @param i string offset, must be i<length
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256 * @param length string length
257 * @param c output UChar32 variable
258 * @see U16_NEXT_UNSAFE
259 * @stable ICU 2.4
260 */
261#define U16_NEXT(s, i, length, c) { \
262 (c)=(s)[(i)++]; \
263 if(U16_IS_LEAD(c)) { \
264 uint16_t __c2; \
265 if((i)<(length) && U16_IS_TRAIL(__c2=(s)[(i)])) { \
266 ++(i); \
267 (c)=U16_GET_SUPPLEMENTARY((c), __c2); \
268 } \
269 } \
270}
271
272/**
273 * Append a code point to a string, overwriting 1 or 2 code units.
274 * The offset points to the current end of the string contents
275 * and is advanced (post-increment).
276 * "Unsafe" macro, assumes a valid code point and sufficient space in the string.
277 * Otherwise, the result is undefined.
278 *
279 * @param s const UChar * string buffer
280 * @param i string offset
281 * @param c code point to append
282 * @see U16_APPEND
283 * @stable ICU 2.4
284 */
285#define U16_APPEND_UNSAFE(s, i, c) { \
286 if((uint32_t)(c)<=0xffff) { \
287 (s)[(i)++]=(uint16_t)(c); \
288 } else { \
289 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
290 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
291 } \
292}
293
294/**
295 * Append a code point to a string, overwriting 1 or 2 code units.
296 * The offset points to the current end of the string contents
297 * and is advanced (post-increment).
298 * "Safe" macro, checks for a valid code point.
299 * If a surrogate pair is written, checks for sufficient space in the string.
300 * If the code point is not valid or a trail surrogate does not fit,
301 * then isError is set to TRUE.
302 *
303 * @param s const UChar * string buffer
93a37866 304 * @param i string offset, must be i<capacity
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305 * @param capacity size of the string buffer
306 * @param c code point to append
307 * @param isError output UBool set to TRUE if an error occurs, otherwise not modified
308 * @see U16_APPEND_UNSAFE
309 * @stable ICU 2.4
310 */
311#define U16_APPEND(s, i, capacity, c, isError) { \
312 if((uint32_t)(c)<=0xffff) { \
313 (s)[(i)++]=(uint16_t)(c); \
314 } else if((uint32_t)(c)<=0x10ffff && (i)+1<(capacity)) { \
315 (s)[(i)++]=(uint16_t)(((c)>>10)+0xd7c0); \
316 (s)[(i)++]=(uint16_t)(((c)&0x3ff)|0xdc00); \
317 } else /* c>0x10ffff or not enough space */ { \
318 (isError)=TRUE; \
319 } \
320}
321
322/**
323 * Advance the string offset from one code point boundary to the next.
324 * (Post-incrementing iteration.)
325 * "Unsafe" macro, assumes well-formed UTF-16.
326 *
327 * @param s const UChar * string
328 * @param i string offset
329 * @see U16_FWD_1
330 * @stable ICU 2.4
331 */
332#define U16_FWD_1_UNSAFE(s, i) { \
333 if(U16_IS_LEAD((s)[(i)++])) { \
334 ++(i); \
335 } \
336}
337
338/**
339 * Advance the string offset from one code point boundary to the next.
340 * (Post-incrementing iteration.)
341 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
342 *
343 * @param s const UChar * string
93a37866 344 * @param i string offset, must be i<length
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345 * @param length string length
346 * @see U16_FWD_1_UNSAFE
347 * @stable ICU 2.4
348 */
349#define U16_FWD_1(s, i, length) { \
350 if(U16_IS_LEAD((s)[(i)++]) && (i)<(length) && U16_IS_TRAIL((s)[i])) { \
351 ++(i); \
352 } \
353}
354
355/**
356 * Advance the string offset from one code point boundary to the n-th next one,
357 * i.e., move forward by n code points.
358 * (Post-incrementing iteration.)
359 * "Unsafe" macro, assumes well-formed UTF-16.
360 *
361 * @param s const UChar * string
362 * @param i string offset
363 * @param n number of code points to skip
364 * @see U16_FWD_N
365 * @stable ICU 2.4
366 */
367#define U16_FWD_N_UNSAFE(s, i, n) { \
368 int32_t __N=(n); \
369 while(__N>0) { \
370 U16_FWD_1_UNSAFE(s, i); \
371 --__N; \
372 } \
373}
374
375/**
376 * Advance the string offset from one code point boundary to the n-th next one,
377 * i.e., move forward by n code points.
378 * (Post-incrementing iteration.)
379 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
380 *
381 * @param s const UChar * string
93a37866 382 * @param i string offset, must be i<length
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383 * @param length string length
384 * @param n number of code points to skip
385 * @see U16_FWD_N_UNSAFE
386 * @stable ICU 2.4
387 */
388#define U16_FWD_N(s, i, length, n) { \
389 int32_t __N=(n); \
390 while(__N>0 && (i)<(length)) { \
391 U16_FWD_1(s, i, length); \
392 --__N; \
393 } \
394}
395
396/**
397 * Adjust a random-access offset to a code point boundary
398 * at the start of a code point.
399 * If the offset points to the trail surrogate of a surrogate pair,
400 * then the offset is decremented.
401 * Otherwise, it is not modified.
402 * "Unsafe" macro, assumes well-formed UTF-16.
403 *
404 * @param s const UChar * string
405 * @param i string offset
406 * @see U16_SET_CP_START
407 * @stable ICU 2.4
408 */
409#define U16_SET_CP_START_UNSAFE(s, i) { \
410 if(U16_IS_TRAIL((s)[i])) { \
411 --(i); \
412 } \
413}
414
415/**
416 * Adjust a random-access offset to a code point boundary
417 * at the start of a code point.
418 * If the offset points to the trail surrogate of a surrogate pair,
419 * then the offset is decremented.
420 * Otherwise, it is not modified.
421 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
422 *
423 * @param s const UChar * string
424 * @param start starting string offset (usually 0)
93a37866 425 * @param i string offset, must be start<=i
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426 * @see U16_SET_CP_START_UNSAFE
427 * @stable ICU 2.4
428 */
429#define U16_SET_CP_START(s, start, i) { \
430 if(U16_IS_TRAIL((s)[i]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
431 --(i); \
432 } \
433}
434
435/* definitions with backward iteration -------------------------------------- */
436
437/**
438 * Move the string offset from one code point boundary to the previous one
439 * and get the code point between them.
440 * (Pre-decrementing backward iteration.)
441 * "Unsafe" macro, assumes well-formed UTF-16.
442 *
443 * The input offset may be the same as the string length.
444 * If the offset is behind a trail surrogate unit
445 * for a supplementary code point, then the macro will read
446 * the preceding lead surrogate as well.
447 * If the offset is behind a lead surrogate, then that itself
448 * will be returned as the code point.
449 * The result is undefined if the offset is behind a single, unpaired trail surrogate.
450 *
451 * @param s const UChar * string
452 * @param i string offset
453 * @param c output UChar32 variable
454 * @see U16_PREV
455 * @stable ICU 2.4
456 */
457#define U16_PREV_UNSAFE(s, i, c) { \
458 (c)=(s)[--(i)]; \
459 if(U16_IS_TRAIL(c)) { \
460 (c)=U16_GET_SUPPLEMENTARY((s)[--(i)], (c)); \
461 } \
462}
463
464/**
465 * Move the string offset from one code point boundary to the previous one
466 * and get the code point between them.
467 * (Pre-decrementing backward iteration.)
468 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
469 *
470 * The input offset may be the same as the string length.
471 * If the offset is behind a trail surrogate unit
472 * for a supplementary code point, then the macro will read
473 * the preceding lead surrogate as well.
474 * If the offset is behind a lead surrogate or behind a single, unpaired
475 * trail surrogate, then that itself
476 * will be returned as the code point.
477 *
478 * @param s const UChar * string
479 * @param start starting string offset (usually 0)
93a37866 480 * @param i string offset, must be start<i
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481 * @param c output UChar32 variable
482 * @see U16_PREV_UNSAFE
483 * @stable ICU 2.4
484 */
485#define U16_PREV(s, start, i, c) { \
486 (c)=(s)[--(i)]; \
487 if(U16_IS_TRAIL(c)) { \
488 uint16_t __c2; \
489 if((i)>(start) && U16_IS_LEAD(__c2=(s)[(i)-1])) { \
490 --(i); \
491 (c)=U16_GET_SUPPLEMENTARY(__c2, (c)); \
492 } \
493 } \
494}
495
496/**
497 * Move the string offset from one code point boundary to the previous one.
498 * (Pre-decrementing backward iteration.)
499 * The input offset may be the same as the string length.
500 * "Unsafe" macro, assumes well-formed UTF-16.
501 *
502 * @param s const UChar * string
503 * @param i string offset
504 * @see U16_BACK_1
505 * @stable ICU 2.4
506 */
507#define U16_BACK_1_UNSAFE(s, i) { \
508 if(U16_IS_TRAIL((s)[--(i)])) { \
509 --(i); \
510 } \
511}
512
513/**
514 * Move the string offset from one code point boundary to the previous one.
515 * (Pre-decrementing backward iteration.)
516 * The input offset may be the same as the string length.
517 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
518 *
519 * @param s const UChar * string
520 * @param start starting string offset (usually 0)
93a37866 521 * @param i string offset, must be start<i
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522 * @see U16_BACK_1_UNSAFE
523 * @stable ICU 2.4
524 */
525#define U16_BACK_1(s, start, i) { \
526 if(U16_IS_TRAIL((s)[--(i)]) && (i)>(start) && U16_IS_LEAD((s)[(i)-1])) { \
527 --(i); \
528 } \
529}
530
531/**
532 * Move the string offset from one code point boundary to the n-th one before it,
533 * i.e., move backward by n code points.
534 * (Pre-decrementing backward iteration.)
535 * The input offset may be the same as the string length.
536 * "Unsafe" macro, assumes well-formed UTF-16.
537 *
538 * @param s const UChar * string
539 * @param i string offset
540 * @param n number of code points to skip
541 * @see U16_BACK_N
542 * @stable ICU 2.4
543 */
544#define U16_BACK_N_UNSAFE(s, i, n) { \
545 int32_t __N=(n); \
546 while(__N>0) { \
547 U16_BACK_1_UNSAFE(s, i); \
548 --__N; \
549 } \
550}
551
552/**
553 * Move the string offset from one code point boundary to the n-th one before it,
554 * i.e., move backward by n code points.
555 * (Pre-decrementing backward iteration.)
556 * The input offset may be the same as the string length.
557 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
558 *
559 * @param s const UChar * string
560 * @param start start of string
93a37866 561 * @param i string offset, must be start<i
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562 * @param n number of code points to skip
563 * @see U16_BACK_N_UNSAFE
564 * @stable ICU 2.4
565 */
566#define U16_BACK_N(s, start, i, n) { \
567 int32_t __N=(n); \
568 while(__N>0 && (i)>(start)) { \
569 U16_BACK_1(s, start, i); \
570 --__N; \
571 } \
572}
573
574/**
575 * Adjust a random-access offset to a code point boundary after a code point.
576 * If the offset is behind the lead surrogate of a surrogate pair,
577 * then the offset is incremented.
578 * Otherwise, it is not modified.
579 * The input offset may be the same as the string length.
580 * "Unsafe" macro, assumes well-formed UTF-16.
581 *
582 * @param s const UChar * string
583 * @param i string offset
584 * @see U16_SET_CP_LIMIT
585 * @stable ICU 2.4
586 */
587#define U16_SET_CP_LIMIT_UNSAFE(s, i) { \
588 if(U16_IS_LEAD((s)[(i)-1])) { \
589 ++(i); \
590 } \
591}
592
593/**
594 * Adjust a random-access offset to a code point boundary after a code point.
595 * If the offset is behind the lead surrogate of a surrogate pair,
596 * then the offset is incremented.
597 * Otherwise, it is not modified.
598 * The input offset may be the same as the string length.
599 * "Safe" macro, handles unpaired surrogates and checks for string boundaries.
600 *
601 * @param s const UChar * string
602 * @param start starting string offset (usually 0)
603 * @param i string offset, start<=i<=length
604 * @param length string length
605 * @see U16_SET_CP_LIMIT_UNSAFE
606 * @stable ICU 2.4
607 */
608#define U16_SET_CP_LIMIT(s, start, i, length) { \
609 if((start)<(i) && (i)<(length) && U16_IS_LEAD((s)[(i)-1]) && U16_IS_TRAIL((s)[i])) { \
610 ++(i); \
611 } \
612}
613
614#endif